The U.S. criminal indictment against Canadian Ishiang Shih grabs attention. It is not everyday, after all, that a professor at a prestigious university is charged with illegally exporting advanced technology to China.

But the now-retired McGill faculty member is just one among numerous scientists of Chinese descent caught up recently in a controversial American dragnet, its goal to combat economic espionage by Beijing.

Researchers for private companies and universities have been charged with various crimes, as well as non-Chinese intelligence agents and civil servants. Others have been fired summarily. One Washington, D.C. lawyer says he represents three-dozen Chinese-American scientists who have been charged or put under suspicion by federal authorities.

They now feel unfairly scrutinized, stigmatized and on edge – because of their Chinese ethnicity alone

The U.S. Justice Department, which concentrated its efforts on the issue by launching a new “China Initiative” last year, says it’s trying to combat Beijing’s s well-documented campaign to acquire foreign technological secrets by any means.

Some prominent critics, however, suggest America’s trade war with China has propelled police on a witch hunt against east-Asian researchers.

“In managing these risks, we must take great care not to create a toxic atmosphere of unfounded suspicion and fear,” Massachusetts Institute of Technology president Rafael Reif wrote in an open letter last month.

“Yet faculty members, post-docs, research staff and students tell me that, in their dealings with government agencies, they now feel unfairly scrutinized, stigmatized and on edge – because of their Chinese ethnicity alone.”

A Chinese American academic who was earlier charged with sending secrets to China – then cleared because agents misunderstood the nature of his work – is suing the U.S. government, helped by the American Civil Liberties Union.

“I think what is wrong is to single out a particular ethnic group for surveillance and prosecution,” Xiaoxing Xi, the former physics department chair at Philadelphia’s Temple University, said in an interview Thursday. “That is racial profiling.”

In Canada, meanwhile, the RCMP says it has no country-specific investigation program, while universities report they are working with China to their “mutual benefit.”

Yet there is certainly widespread consensus that China often uses illegal methods to acquire technology developed elsewhere, for military use or to give domestic companies a competitive leg-up.

Trump administration officials have been blunt in describing the threat they perceive from the research community.

FBI offices across the U.S. see evidence China uses “non-traditional collectors” of such intelligence, including Chinese students, professors and scientists, FBI Director Christopher Wray told a congressional hearing last year.

“I think the level of naivete on the part of the academic sector about this creates its own issues,” he said. “They’re exploiting the very open research and development environment that we have, which we all revere, but they’re taking advantage of it.”

They’re exploiting the very open research and development environment that we have

Montreal’s Shih was indicted last year along with brother Yi-Chi – a fellow electrical engineer who has worked at UCLA – with conspiring to send advanced computer chips to China, contrary to export restrictions. Yi-Chi was convicted recently, and a source said the U.S. has asked Canada to extradite Ishiang, who retired from McGill last year.

But the California-based brother’s lawyer said the case was a “tragic” miscarriage of justice that saw the jury deprived of key evidence. Yi-Chi had designed the chip himself, and the American company whose design tools he used actually has a large operation – and half its workforce – in China.

Broader concerns are being raised about the idea of going after researchers of one race, and the nature of many of the prosecutions to date.

Peter Zeidenberg, a Washington, D.C. lawyer who represented Xi, said agents have completely misconstrued the science and reached wrong conclusions in a “very large percentage” of the three-dozen or so such cases he’s taken on.

“They do not understand what is going on and they’re assuming the worst,” he told a recent panel at New York City’s China Institute. “It’s becoming a criminalization based on a paranoia.”

Charges were dropped against Xi when police acknowledged the physicist had not sent to China the type of technology they claimed he had. Even if he had done so, says Xi, that science is publicly available – not a secret.

FBI Director Christopher Wray: “I think the level of naivete on the part of the academic sector about this creates its own issues.”Nicholas Kamm/AFP/Getty Images/File

Regardless, he said the 2015 prosecution has had a devastating effect, with his federal grants almost disappearing and the number of students and post-doctoral fellows on his research team shrinking to three from 15.

“The impact on my career is huge,” he said. And now, “I worry constantly that the government will twist something I do in order to lay charges.”

In Canada, meanwhile, there is little evidence security agencies have taken a pro-active approach to any China threat on campuses.

The RCMP “does not have an investigative unit targeting any particular foreign entity,” said Cpl. Caroline Duval, a spokeswoman for the force.

And a spokeswoman for Canadian universities’ umbrella group said she is aware of no warnings of the type reportedly issued by American security agencies to colleges about economic espionage and China.

“Many universities have very productive research relationships with China that are mutually beneficial,” added Universities Canada official Alison Evans by email.

Others were more ambiguous.

At McGill, 15 personnel met with Canadian Security Intelligence Service officials last December about “potential issues surrounding collaborations with companies outside of Canada,” said spokesman Vincent Campbell Allaire. He wouldn’t elaborate, or say if those issues involved China.

The University of Toronto said only that it has heard from the government about “general security issues” but has received no requests “regarding specific individuals”